fix(web): 统一 API 请求语义并修复鼠标移动发送间隔

- 新增统一 request：同时处理 HTTP 非 2xx 与 success=false，并用 i18n toast 提示错误
- api/index.ts 与 api/config.ts 统一使用同一 request，避免错误处理不一致
- "发送间隔" 仅控制鼠标移动事件频率，WebRTC/WS 行为一致，不影响点击/滚轮

web/src/api/request.ts

@@ -0,0 +1,133 @@
+import { toast } from 'vue-sonner'
+import i18n from '@/i18n'
+
+const API_BASE = '/api'
+
+// Toast debounce mechanism - prevent toast spam (5 seconds)
+const toastDebounceMap = new Map<string, number>()
+const TOAST_DEBOUNCE_TIME = 5000
+
+function shouldShowToast(key: string): boolean {
+  const now = Date.now()
+  const lastToastTime = toastDebounceMap.get(key)
+
+  if (!lastToastTime || now - lastToastTime >= TOAST_DEBOUNCE_TIME) {
+    toastDebounceMap.set(key, now)
+    return true
+  }
+
+  return false
+}
+
+function t(key: string, params?: Record<string, unknown>): string {
+  return String(i18n.global.t(key, params as any))
+}
+
+export class ApiError extends Error {
+  status: number
+
+  constructor(status: number, message: string) {
+    super(message)
+    this.name = 'ApiError'
+    this.status = status
+  }
+}
+
+export interface ApiRequestConfig {
+  /**
+   * Enable toast notifications on errors.
+   * Defaults to true to match existing behavior in api/index.ts.
+   */
+  toastOnError?: boolean
+  /**
+   * Toast debounce key. Defaults to `error_${endpoint}`.
+   */
+  toastKey?: string
+}
+
+function getToastKey(endpoint: string, config?: ApiRequestConfig): string {
+  return config?.toastKey ?? `error_${endpoint}`
+}
+
+function getErrorMessage(data: unknown, fallback: string): string {
+  if (data && typeof data === 'object') {
+    const message = (data as any).message
+    if (typeof message === 'string' && message.trim()) return message
+  }
+  return fallback
+}
+
+export async function request<T>(
+  endpoint: string,
+  options: RequestInit = {},
+  config: ApiRequestConfig = {}
+): Promise<T> {
+  const url = `${API_BASE}${endpoint}`
+  const toastOnError = config.toastOnError !== false
+  const toastKey = getToastKey(endpoint, config)
+
+  try {
+    const response = await fetch(url, {
+      ...options,
+      headers: {
+        'Content-Type': 'application/json',
+        ...options.headers,
+      },
+      credentials: 'include',
+    })
+
+    const data = await response.json().catch(() => null)
+
+    // Handle HTTP errors (in case backend returns non-2xx)
+    if (!response.ok) {
+      const message = getErrorMessage(data, `HTTP ${response.status}`)
+      if (toastOnError && shouldShowToast(toastKey)) {
+        toast.error(t('api.operationFailed'), {
+          description: message,
+          duration: 4000,
+        })
+      }
+      throw new ApiError(response.status, message)
+    }
+
+    // Handle backend "success=false" convention (even when HTTP is 200)
+    if (data && typeof (data as any).success === 'boolean' && !(data as any).success) {
+      const message = getErrorMessage(data, t('api.operationFailedDesc'))
+
+      if (toastOnError && shouldShowToast(toastKey)) {
+        toast.error(t('api.operationFailed'), {
+          description: message,
+          duration: 4000,
+        })
+      }
+
+      throw new ApiError(response.status, message)
+    }
+
+    // If response body isn't JSON (or empty), treat as failure for callers expecting JSON.
+    if (data === null) {
+      const message = t('api.parseResponseFailed')
+      if (toastOnError && shouldShowToast(toastKey)) {
+        toast.error(t('api.operationFailed'), {
+          description: message,
+          duration: 4000,
+        })
+      }
+      throw new ApiError(response.status, message)
+    }
+
+    return data as T
+  } catch (error) {
+    if (error instanceof ApiError) throw error
+
+    if (toastOnError && shouldShowToast('network_error')) {
+      toast.error(t('api.networkError'), {
+        description: t('api.networkErrorDesc'),
+        duration: 4000,
+      })
+    }
+
+    throw new ApiError(0, t('api.networkError'))
+  }
+}
+